ADSORPTION AND THERMAL-DECOMPOSITION OF METHANOL ON 3D TRANSITION-METAL ALUMINIDES - FEAL(110), NIAL AND TIAL

The adsorption and thermal decomposition of methanol on FeAl(110), pol ycrystalline NiAl, and polycrystalline TiAl have been investigated. Te mperature-programmed desorption (TPD) and ultraviolet and X-rav photoe lectron spectroscopies (UPS and XPS) are used to investigate the elect ronic structure and thermal decomposition reactions on 3d transition m etal aluminide surfaces. Methane and hydrogen are the two primary prod ucts that result from methanol decomposition on all the 3d transition metal aluminides. UPS of CH3OH/FeAl(110) and CH3OH/NiAl at 200 and 270 K, respectively, supports the existence of a methoxy intermediate (CH 3O) on the Al component of FeAl(110) and NiAl. XPS results support a s urface picture that has carbon chemisorbing on 'transition metal'' sit es and the oxygen remaining on Al during the decomposition of the inte rmediate species. The peak temperatures of methane desorption from TiA l, FeAl(110), and NiAl are 450, 550, and 590 K, respectively.